Important:
• | Engine temperature, accessory load, and elevation level will affect engine
vacuum. |
• | Vacuum readings will decrease by approximately 2.7 kPa (0.8 in Hg)
for every 305 m (1000 ft) of elevation above sea level. |
- Disconnect the engine vacuum hose from the vacuum brake booster check valve.
- Install a vacuum gauge to the engine vacuum hose.
- Start the engine and allow the engine to idle until normal operating temperatures
are reached.
- With the vehicle in PARK or NEUTRAL with the park brake on, the engine
idling, and the air conditioning (A/C) system OFF, check to see if the engine vacuum
reading is within the specified normal engine vacuum range.
Specification
47-68 kPa (14-20 in Hg)
- Turn the ignition OFF.
- If the engine vacuum reading is within the specified normal range, proceed
to step 10.
- If the engine vacuum reading is NOT within the specified normal range,
inspect the engine vacuum hose for the following conditions.
• | Loose connection to the engine. |
• | Collapse, deformation or contamination. |
• | Cracks, cuts, or brittleness. |
- If any of these conditions were found with the engine vacuum hose, replace
the hose, then repeat steps 2 [dash ] 4.
- If none of these conditions were found with the engine vacuum hose, then
there is an engine vacuum source condition, check the engine vacuum system.
- Remove the vacuum brake booster check valve from the booster.
- Install the check valve to the engine vacuum hose.
- Install the vacuum gauge to the check valve.
- Start the engine and allow the engine to idle in park or neutral with
the park brake on and with the A/C system OFF, until normal operating temperatures
are reached.
- Turn the ignition OFF.
- Visually inspect the engine vacuum reading is maintained within the specified
normal engine vacuum range.
Specification
47-68 kPa (14-20 in Hg)
- If the engine vacuum reading is maintained within the specified normal
range, proceed to step 18.
- If the engine vacuum reading is NOT maintained within the specified normal
range, replace the vacuum brake booster check valve, then repeat steps 11 15.
- Inspect the vacuum brake booster check valve grommet for the following
conditions:
• | Loose connection to the vacuum brake booster. |
• | Deformation or contamination. |
• | Cracks, cuts or brittleness. |
- If any of these conditions were found with the check valve grommet, replace
the grommet.